package org.apache.maven;

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

import java.util.Collection;
import java.util.Collections;
import java.util.HashSet;
import java.util.Iterator;
import java.util.LinkedHashSet;
import java.util.Set;

import org.apache.maven.artifact.Artifact;
import org.apache.maven.artifact.ArtifactUtils;
import org.apache.maven.artifact.resolver.ArtifactNotFoundException;
import org.apache.maven.artifact.resolver.ArtifactResolutionException;
import org.apache.maven.artifact.resolver.ArtifactResolutionRequest;
import org.apache.maven.artifact.resolver.ArtifactResolutionResult;
import org.apache.maven.artifact.resolver.MultipleArtifactsNotFoundException;
import org.apache.maven.artifact.resolver.ResolutionErrorHandler;
import org.apache.maven.artifact.resolver.filter.CumulativeScopeArtifactFilter;
import org.apache.maven.execution.MavenSession;
import org.apache.maven.project.MavenProject;
import org.apache.maven.project.artifact.ProjectArtifact;
import org.apache.maven.repository.RepositorySystem;
import org.codehaus.plexus.component.annotations.Component;
import org.codehaus.plexus.component.annotations.Requirement;

@Component(role = ProjectDependenciesResolver.class)
public class DefaultProjectDependenciesResolver implements ProjectDependenciesResolver {

  @Requirement
  private RepositorySystem repositorySystem;

  @Requirement
  private ResolutionErrorHandler resolutionErrorHandler;

  public Set<Artifact> resolve(MavenProject project, Collection<String> scopesToResolve, MavenSession session)
      throws ArtifactResolutionException, ArtifactNotFoundException {
    return resolve(Collections.singleton(project), scopesToResolve, session);
  }

  public Set<Artifact> resolve(MavenProject project, Collection<String> scopesToCollect,
      Collection<String> scopesToResolve, MavenSession session)
      throws ArtifactResolutionException, ArtifactNotFoundException {
    Set<MavenProject> mavenProjects = Collections.singleton(project);
    return resolveImpl(mavenProjects, scopesToCollect, scopesToResolve, session, getIgnorableArtifacts(mavenProjects));
  }

  public Set<Artifact> resolve(Collection<? extends MavenProject> projects, Collection<String> scopesToResolve,
      MavenSession session) throws ArtifactResolutionException, ArtifactNotFoundException {
    return resolveImpl(projects, null, scopesToResolve, session, getIgnorableArtifacts(projects));
  }

  public Set<Artifact> resolve(MavenProject project, Collection<String> scopesToCollect,
      Collection<String> scopesToResolve, MavenSession session, Set<Artifact> ignoreableArtifacts)
      throws ArtifactResolutionException, ArtifactNotFoundException {
    return resolveImpl(Collections.singleton(project), scopesToCollect, scopesToResolve, session,
        getIgnorableArtifacts(ignoreableArtifacts));
  }

  private Set<Artifact> resolveImpl(Collection<? extends MavenProject> projects, Collection<String> scopesToCollect,
      Collection<String> scopesToResolve, MavenSession session, Set<String> projectIds)
      throws ArtifactResolutionException, ArtifactNotFoundException {
    Set<Artifact> resolved = new LinkedHashSet<Artifact>();

    if (projects == null || projects.isEmpty()) {
      return resolved;
    }

    if ((scopesToCollect == null || scopesToCollect.isEmpty())
        && (scopesToResolve == null || scopesToResolve.isEmpty())) {
      return resolved;
    }

    /*
     * 
     * Logic for transitive global exclusions
     * 
     * List<String> exclusions = new ArrayList<String>();
     * 
     * for ( Dependency d : project.getDependencies() ) { if ( d.getExclusions() != null ) { for (
     * Exclusion e : d.getExclusions() ) { exclusions.add( e.getGroupId() + ":" + e.getArtifactId()
     * ); } } }
     * 
     * ArtifactFilter scopeFilter = new ScopeArtifactFilter( scope );
     * 
     * ArtifactFilter filter;
     * 
     * if ( ! exclusions.isEmpty() ) { filter = new AndArtifactFilter( Arrays.asList( new
     * ArtifactFilter[]{ new ExcludesArtifactFilter( exclusions ), scopeFilter } ) ); } else {
     * filter = scopeFilter; }
     */

    CumulativeScopeArtifactFilter resolutionScopeFilter = new CumulativeScopeArtifactFilter(scopesToResolve);

    CumulativeScopeArtifactFilter collectionScopeFilter = new CumulativeScopeArtifactFilter(scopesToCollect);
    collectionScopeFilter = new CumulativeScopeArtifactFilter(collectionScopeFilter, resolutionScopeFilter);

    ArtifactResolutionRequest request = new ArtifactResolutionRequest().setResolveRoot(false)
        .setResolveTransitively(true).setCollectionFilter(collectionScopeFilter)
        .setResolutionFilter(resolutionScopeFilter).setLocalRepository(session.getLocalRepository())
        .setOffline(session.isOffline()).setForceUpdate(session.getRequest().isUpdateSnapshots());
    request.setServers(session.getRequest().getServers());
    request.setMirrors(session.getRequest().getMirrors());
    request.setProxies(session.getRequest().getProxies());

    for (MavenProject project : projects) {
      request.setArtifact(new ProjectArtifact(project));
      request.setArtifactDependencies(project.getDependencyArtifacts());
      request.setManagedVersionMap(project.getManagedVersionMap());
      request.setRemoteRepositories(project.getRemoteArtifactRepositories());

      ArtifactResolutionResult result = repositorySystem.resolve(request);

      try {
        resolutionErrorHandler.throwErrors(request, result);
      } catch (MultipleArtifactsNotFoundException e) {

        Collection<Artifact> missing = new HashSet<Artifact>(e.getMissingArtifacts());

        for (Iterator<Artifact> it = missing.iterator(); it.hasNext();) {
          String key = ArtifactUtils.key(it.next());
          if (projectIds.contains(key)) {
            it.remove();
          }
        }

        if (!missing.isEmpty()) {
          throw e;
        }
      }

      resolved.addAll(result.getArtifacts());
    }

    return resolved;
  }

  private Set<String> getIgnorableArtifacts(Collection<? extends MavenProject> projects) {
    Set<String> projectIds = new HashSet<String>(projects.size() * 2);

    for (MavenProject p : projects) {
      String key = ArtifactUtils.key(p.getGroupId(), p.getArtifactId(), p.getVersion());
      projectIds.add(key);
    }
    return projectIds;
  }

  private Set<String> getIgnorableArtifacts(Iterable<Artifact> artifactIterable) {
    Set<String> projectIds = new HashSet<String>();

    for (Artifact artifact : artifactIterable) {
      String key = ArtifactUtils.key(artifact);
      projectIds.add(key);
    }
    return projectIds;
  }

}
